DBCherry,
I think a 91 four stroke would be plenty for that plane, The 91 two stroke was almost unlimited at less than half throttle. Unless of course you want to hang from the prop.

Just be fussy on the cabane alignment, the plywood blocks that hold the cabanes to the fuse will need to be shaved and adjusted to get the right incidence. Also, fuel proof the fuel tank compartment before its all put together or you will find out the hard way how difficult it is to get in there.

Good luck and get it done.